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Commit98b4620

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pathman: documentation
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‎contrib/pg_pathman/README.md‎

Lines changed: 41 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -129,6 +129,27 @@ This will create new partitions but data will still be in the parent table. To m
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```
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SELECT partition_data('hash_rel');
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```
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Here is an example of the query with filtering by partitioning key and its plan:
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```
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SELECT * FROM hash_rel WHERE value = 1234;
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id | value
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------+-------
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1234 | 1234
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EXPLAIN SELECT * FROM hash_rel WHERE value = 1234;
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QUERY PLAN
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-----------------------------------------------------------------
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Append (cost=0.00..2.00 rows=0 width=0)
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-> Seq Scan on hash_rel_34 (cost=0.00..2.00 rows=0 width=0)
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Filter: (value = 1234)
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```
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Note that pg_pathman exludes parent table from the query plan. To access parent table use ONLY modifier:
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```
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EXPLAIN SELECT * FROM ONLY hash_rel;
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QUERY PLAN
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--------------------------------------------------------
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Seq Scan on hash_rel (cost=0.00..0.00 rows=1 width=8)
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```
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###RANGE
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Consider an example of RANGE partitioning. Create a table with numerical or date or timestamp column:
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```
@@ -156,12 +177,29 @@ SELECT split_range_partition('range_rel_1', '2010-02-15'::date);
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Now let's create new partition. You can use append_partition() or prepend_partition() functions:
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```
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SELECT append_partition('range_rel');
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SELECT prepend_partition('range_rel');
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```
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Here is an example of the query with filtering by partitioning key and its plan:
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```
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SELECT * FROM range_rel WHERE dt >= '2012-04-30' AND dt <= '2012-05-01';
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id | dt
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-----+---------------------
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851 | 2012-04-30 00:00:00
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852 | 2012-05-01 00:00:00
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EXPLAIN SELECT * FROM range_rel WHERE dt >= '2012-04-30' AND dt <= '2012-05-01';
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QUERY PLAN
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----------------------------------------------------------------------------
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Append (cost=0.00..60.80 rows=0 width=0)
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-> Seq Scan on range_rel_28 (cost=0.00..30.40 rows=0 width=0)
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Filter: (dt >= '2012-04-30 00:00:00'::timestamp without time zone)
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-> Seq Scan on range_rel_29 (cost=0.00..30.40 rows=0 width=0)
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Filter: (dt <= '2012-05-01 00:00:00'::timestamp without time zone)
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```
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###Disable pg_pathman
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To disable pg_pathman for some previously partitioned table usedisable_pathman() function:
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To disable pg_pathman for some previously partitioned table usedisable_partitioning() function:
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```
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SELECTdisable_pathman('range_rel');
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SELECTdisable_partitioning('range_rel');
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```
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All sections and data will stay available and will be handled by standard PostgreSQL partitioning mechanism.
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###Manual partitions management

‎contrib/pg_pathman/README.rus.md‎

Lines changed: 43 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -131,6 +131,28 @@ SELECT create_hash_partitions('hash_rel', 'value', 100);
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```
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SELECT partition_data('hash_rel');
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```
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Пример построения плана для запроса с фильтрацией по ключевому полю:
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```
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SELECT * FROM hash_rel WHERE value = 1234;
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id | value
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------+-------
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1234 | 1234
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EXPLAIN SELECT * FROM hash_rel WHERE value = 1234;
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QUERY PLAN
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-----------------------------------------------------------------
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Append (cost=0.00..2.00 rows=0 width=0)
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-> Seq Scan on hash_rel_34 (cost=0.00..2.00 rows=0 width=0)
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Filter: (value = 1234)
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```
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Стоит отметить, что pg_pathman исключает из плана запроса родительскую таблицу, и чтобы получить данные из нее, следует использовать модификатор ONLY:
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```
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EXPLAIN SELECT * FROM ONLY hash_rel;
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QUERY PLAN
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--------------------------------------------------------
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Seq Scan on hash_rel (cost=0.00..0.00 rows=1 width=8)
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```
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###RANGE
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Пример секционирования таблицы с использованием стратегии RANGE.
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```
@@ -159,12 +181,30 @@ SELECT split_range_partition('range_rel_1', '2010-02-15'::date);
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```
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Добавим новую секцию в конец списка секций:
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```
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SELECT append_partition('range_rel')
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SELECT append_partition('range_rel');
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```
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Пример построения плана для запроса с фильтрацией по ключевому полю:
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```
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SELECT * FROM range_rel WHERE dt >= '2012-04-30' AND dt <= '2012-05-01';
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id | dt
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-----+---------------------
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851 | 2012-04-30 00:00:00
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852 | 2012-05-01 00:00:00
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EXPLAIN SELECT * FROM range_rel WHERE dt >= '2012-04-30' AND dt <= '2012-05-01';
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QUERY PLAN
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----------------------------------------------------------------------------
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Append (cost=0.00..60.80 rows=0 width=0)
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-> Seq Scan on range_rel_28 (cost=0.00..30.40 rows=0 width=0)
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Filter: (dt >= '2012-04-30 00:00:00'::timestamp without time zone)
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-> Seq Scan on range_rel_29 (cost=0.00..30.40 rows=0 width=0)
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Filter: (dt <= '2012-05-01 00:00:00'::timestamp without time zone)
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```
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###Деакцивация pathman
165-
Деактивировать pathman для некоторой ранее разделенной таблицы можно следующей командойdisable_pathman():
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Деактивировать pathman для некоторой ранее разделенной таблицы можно следующей командойdisable_partitioning():
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```
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SELECTdisable_pathman('range_rel');
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SELECTdisable_partitioning('range_rel');
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```
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Все созданные секции и данные останутся по прежнему доступны и будут обрабатываться стандартным планировщиком PostgreSQL.
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###Ручное управление секциями

‎contrib/pg_pathman/sql/init.sql‎

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Original file line numberDiff line numberDiff line change
@@ -78,10 +78,10 @@ RETURNS VOID AS
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$$
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BEGIN
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DELETEFROM @extschema@.pathman_configWHERE relname= relation;
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EXECUTE format('DROPTRIGGER %s_insert_trigger_func ON %1$s', relation);
81+
EXECUTE format('DROPFUNCTION IF EXISTS %s_insert_trigger_func() CASCADE', relation);
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8383
/* Notify backend about changes*/
84-
PERFORMpg_pathman_on_remove_partitions(relation::regclass::integer);
84+
PERFORMon_remove_partitions(relation::regclass::integer);
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END
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$$
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LANGUAGE plpgsql;

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